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PUBLICATIONS
TITLE
YEAR
Autonomous Satellite Detection And Tracking Using Optical Flow
D Zuehlke, D Posada, M Tiwari, T Henderson
In this paper, an autonomous method of satellite detection and tracking in images is implemented using optical flow. Optical flow is used to estimate the image velocities of detected objects in a series of space images. Given that most objects in an image will be stars, the overall image velocity from star motion is used to estimate the image frame-to-frame motion. Objects seen to be moving with velocity profiles distinct from the overall image velocity are then classified as potential resident space objects. The detection algorithm is exercised using both simulated star images and ground-based imagery of satellites. Finally, this algorithm will be tested and compared using a commercial and an open-source software approach to provide the reader two different options based on their need.
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Autonomous Spacecraft Obstacle Avoidance And Trajectory Tracking In Dense Debris Field
M Tiwari, D Zuehlke, T Henderson, RJ Prazenica
In this paper, we implement an autonomous path planning technique using artificial potential functions paired with a direct adaptive controller for spacecraft trajectory tracking through a dense debris field. The debris field is modeled as fixed debris and the spacecraft is modeled using relative orbital dynamics with disturbances. The spacecraft is assumed to be in proximity to a dense debris field that it must navigate through to reach a goal destination. Obstacle avoidance trajectories are generated using model independent artificial potential functions that rely only on the position measurements of the debris with respect to the spacecraft. A direct adaptive controller is implemented to track generated trajectories because it can achieve robust tracking in the presence of model and path uncertainties.
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A Geometric Mechanics Approach to Direct Adaptive Model Predictive Control
CW Hays, M Tiwari, T Henderson, RJ Prazenica
AIAA SCITECH 2022 Forum, 2380
2022
Tracking trajectories about asteroids presents a challenging problem due to the highly perturbed gravitational environment. This highly nonlinear environment tightly couples the attitude and translational motion of spacecraft that must be accounted for in any model. The Special Euclidean Group presents a convenient formalism for modeling the effects of the coupled dynamics about asteroids and allows for the construction of similarly capable control laws. In an effort to conserve fuel and account for unmodelled disturbances, this work presents a direct adaptive-model predictive controller using formulations on the Special Euclidean Group.
Autonomous Template Generation and Matching for Satellite Constellation Tracking
D Zuehlke, M Tiwari, T Henderson
AIAA SCITECH 2022 Forum, 0528
This paper proposes a method of autonomous generation of template images for satellite constellation tracking. An initial template image is formed by determining the locations of several resident space objects (RSOs) in an optical image. A template image of a single RSO (i.e. point-source) is matched against the image to determine these RSO locations. The image locations of detected RSOs are then used to form an initial template image. Once an initial template is formed, subsequent frames are matched via normalized cross-correlation to find the generated template in each image. Specific RSOs are then associated across frames by their known position in the template image. In order to handle time-varying configuration of satellites the template image is periodically updated based on a threshold on correlation, or unsuccessful matching.
2022
2021
Spacecraft dynamics and control in the vicinity of an asteroid is a challenging and exciting problem. Currently, trajectory tracking near asteroid requires extensive knowledge about the asteroid and constant human intervention to successfully plan and execute proximity operation. This work aims to reduce human dependency of these missions from a guidance and controls perspective. In this work, adaptive control and model predictive control are implemented to generating and tracking obstacle avoidance trajectories in asteroid’s vicinity.
@inproceedings{hays2022geometric,
title={A Geometric Mechanics Approach to Direct Adaptive
Model Predictive Control},
author={Hays, Chris W and Tiwari, Madhur and Henderson, Troy and Prazenica, Richard J}, booktitle={AIAA SCITECH 2022 Forum},
pages={2380},
year={2022}
}
@article{tiwari2022direct,
title={Direct-Adaptive Nonlinear MPC for Spacecraft Near Asteroids},
author={Tiwari, Madhur and Coyle, Eric and Prazenica, Richard J},
journal={Aerospace}, volume={9}, number={3},
pages={159}, year={2022},
publisher={MDPI}
}
Spacecraft Body-Frame Hovering Over An Asteroid Using A Direct Adaptive Control Strategy
M Tiwari, RJ Prazenica, T Henderson
AIAA Scitech 2020 Forum, 0226
2020
In this paper, we have implemented a direct adaptive control strategy for the spacecraft hovering problem in the vicinity of an asteroid. The asteroid and spacecraft parameters, including gravitational parameters, solar radiation pressure, inertias and higher order harmonics, are assumed to be unknown. A fully nonlinear dynamical model with McCullagh’s gravitational approximation and solar radiation pressure is implemented. Hovering trajectories are presented in an asteroid fixed body frame. Simulation results show successful trajectory tracking using the direct adaptive control strategy.
@inproceedings{hays2022geometric,
title={A Geometric Mechanics Approach to Direct Adaptive Model Predictive Control},
author={Hays, Chris W and Tiwari, Madhur and Henderson, Troy and Prazenica, Richard J},
booktitle={AIAA SCITECH 2022 Forum},
pages={2380}, year={2022}
}
@article{dadaptive,
title={ADAPTIVE CONTROL FOR PROXIMITY MANEUVERS AROUND ASTEROIDS USING
EXTREME LEARNING MACHINE-BASED GRAVITY FIELD ESTIMATION},
author={D’Ambrosio, Andrea and Conforti, Gabriele and Agostinelli, Ivan and Curti, Fabio}
}
Tracking Reference Orbits Around Asteroids With Unknown Gravitational Parameters Using a Nonlinear Adaptive Controller
M Tiwari, RJ Prazenica, T Henderson
AIAA Scitech 2020 Forum, 0226
2020
In this paper, a nonlinear adaptive controller is implemented to track reference orbit trajectories around asteroids or small bodies. The two-body problem with a rotating reference frame is used to model the dynamics of the spacecraft with respect to the asteroid frame of reference. Gravitational perturbations, solar radiation pressure and other unmodeled dynamics are taken as disturbances to the system model. This type of controller has several advantages over other conventional controllers in the presence of uncertain system properties. Preliminary results shows accurate tracking of desired trajectories around asteroid Ida in the presence of unknown gravitational perturbations.
@inproceedings{tiwari2020spacecraft,
title={SPACECRAFT BODY-FRAME HOVERING OVER AN ASTEROID USING A DIRECT ADAPTIVE
CONTROL STRATEGY},
author={Tiwari, Madhur and Henderson, Troy and Prazenica, Richard J},
booktitle={AAS/AIAA Astrodynamics Specialist Conference},
year={2020}
}
@article{tiwari2021adaptive,
title={Adaptive-Optimal Control of Spacecraft near Asteroids},
author={Tiwari, Madhur},
year={2021}
}
@inproceedings{hays2022geometric,
title={A Geometric Mechanics Approach to Direct Adaptive Model Predictive Control},
author={Hays, Chris W and Tiwari, Madhur and Henderson, Troy and Prazenica, Richard J},
booktitle={AIAA SCITECH 2022 Forum},
pages={2380},
year={2022}
}
@article{tiwariautonomous,
title={AUTONOMOUS SPACECRAFT OBSTACLE AVOIDANCE AND TRAJECTORY TRACKING IN
DENSE DEBRIS FIELD},
author={Tiwari, Madhur and Zuehlke, David and Henderson, Troy and Prazenica, Richard J}
}
@article{stackhouse2020constrained,
title={Constrained Motion Analysis and Control of Spacecraft Asteroid Hovering with
Formulation
Extension in Geometric Mechanics Framework},
author={Stackhouse, Wesley Thomas},
year={2020}
}
@article{dadaptive,
title={ADAPTIVE CONTROL FOR PROXIMITY MANEUVERS AROUND ASTEROIDS USING
EXTREME
LEARNING MACHINE-BASED GRAVITY FIELD ESTIMATION},
author={D’Ambrosio, Andrea and Conforti, Gabriele and Agostinelli, Ivan and Curti, Fabio}
}
Application of Direct Adaptive Control to Autonomous Satellite Docking
N Prabhakar, M Tiwari, T Henderson, RJ Prazenica
AIAA Scitech 2019 Forum, 1520
2019
This paper analyzes a Direct Adaptive Control algorithm applied to an autonomous satellite docking problem. A linearized model of relative motion is used to describe the motion between satellites and an adaptive control algorithm is configured to regulate the position and velocity of the deputy to safely dock with the chief. A discretized control effort is applied to the system to minimize the amount of propellant required and the performance of the system is analyzed via simulation studies. An LQR controller is developed to generate an ideal trajectory for the adaptive system to follow in the presence of J2 disturbances. The adaptive controller is then implemented in simulation of a linearized modified Hills-Clohessy-Wiltshire system with J2 perturbations.
@inproceedings{tiwari2020tracking,
title={Tracking reference orbits around asteroids with unknown gravitational parameters using
a nonlinear adaptive controller},
author={Tiwari, Madhur and Prazenica, Richard J and Henderson, Troy},
booktitle={AIAA Scitech 2020 Forum},
pages={0226},
year={2020}
}
Identifying Spacecraft Configuration Using Deep Neural Networks For Precise Orbit Estimation
M Tiwari, D Zuehlke, T Henderson
AAS/AIAA Spaceflight Mechanics Meeting, Ka’anapali, HI
2019
@article{zuehlke2019space,
title={Space image processing and orbit estimation using small aperture optical systems},
author={Zuehlke, David},
year={2019}
}
@inproceedings{zuehlke2020geostationary,
title={Geostationary Satellite Constellation Tracking and Identification Using Normalized Cross
Correlation},
author={Zuehlke, David and Henderson, Troy},
booktitle={AIAA Scitech 2020 Forum},
pages={0230},
year={2020}
}
Multiresolution-Based 3-D Terrain Estimation Algorithms for Complex Urban Environments
P Vergara, M Tiwari, RJ Prazenica, T Henderson
AIAA Scitech 2019 Forum, 1194
2019
This paper investigates the development of multiresolution-based terrain estimation algorithms, focusing on complex three-dimensional urban environments. The algorithms generate functional terrain representations from point cloud data obtained from the processing of onboard vision and/or LIDAR sensors. Two classes of multiresolution algorithms are considered in this work. First, mathematical learning methods are developed and implemented to generate adaptive terrain representations in terms of piecewise-constant multiresolution basis functions. These algorithms have been applied in previous work for terrain estimation over two-dimensional domains and are extended in this paper for threedimensional domains, resulting in terrain representations in terms of multiresolution occupancy grids. The second class of algorithms corresponds to global-orthogonal mapping (GLO-Map) algorithms, which have been
Compressor Stall, an aerodynamic instability due to abnormal air flow in the compressor resulting in loss of total pressure and compressor performance. One of the reasons of compressor stall is due to rise in static back pressure at compressor exit which may result from an imbalance of incidence angle at the rotor and stator and rotational speed. The paper presents the results of a new axial compressor design with counter rotation and variable RPM. Counter-Rotation is used to push compressor performance during stall by moving the operating point away from surge line with a higher pressure ratio rise. Initially an axial compressor is designed with counter-rotation at design point. The flow is modelled by means of Navier-Stokes computation using the upstream rotor conditions and exit static pressure condition with k-epsilon as the turbulence model. Compressor exit conditions are then changed to stall the compressor. After the compressor stalls the RPM of the counter-rotating stage is varied until the compressor recovers from the stall. This novel idea unlike the conventional stall control systems mitigates the stall without compromising compressor performance, in fact it helps to increase the performance and pressure ratio of the compressor with the means of counter-rotation and variable RPM.
2014
@article{vsajbanova2021conceptual,
title={Conceptual Design of the Axial Compressor Stage with Counter-Rotating Rotors},
author={{\v{S}}ajbanov{\'a}, Krist{\'\i}na and {\v{C}}er{\v{n}}an, Jozef and {\v{S}}kult{\'e}ty,
Filip and Rost{\'a}{\v{s}}, J{\'a}n},
journal={Transportation Research Procedia},
volume={59},
pages={144--153},
year={2021},
publisher={Elsevier}
}
@article{عباسی363بررسی,
title={بررسی اثر تغییرات سرعت در طبقات مختلف بر عملکرد کمپرسور محوری چرخش معکوس},
author={عباسی and ثاراله and علیزاده},
journal={مهندسی مکانیک},
volume={363},
number={2},
pages={21--30},
publisher={دانشگاه صنعتی شریف}
}
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